In the casting of concrete for street curbs, two forms are normally used of which one is placed at right angle with the ground and the other at a slant or acute angle. The concrete is poured in these forms up to the end of the street but must be interrupted before the curve and begin again on the other side of the curve. It is only when the concrete has hardened, that the curve form, made of plywood, may be installed to complete the pouring of the concrete. The methods of making concrete curbs are known from the following patents:
1. Teters in U.S. Pat. No. 1,140,776 in 1915 shows parallel sections held in place by pegs.
2. C-channels are used by Heltzel U.S. Pat. No. 1,644,584 in 1927, of which one is perpendicular to the ground and the other at an angle, but for a straight section only.
3. Harrold U.S. Pat. No. 1,770,518 utilizes parallel flat steel for a 90.degree. curve.
4. In 1933, Heltzel exposes a vertical adjustment creating a Vee opening at the ends of forms, to account for up and down adjustments in terrain U.S. Pat. No. 1,939,007.
5. Von Drasek reports in 1968, U.S. Pat. No. 3,385,552, a concave/convex arrangement to facilitate the curving of flat steel forms.
6. A spring is used in conjunction with the supporting pegs, Stegmeier U.S. Pat. No. 4,340,200 in 1982.
But none of the above describes completely the characteristics of my invention.